IADR Abstract Archives
Long term NF-kB activation causes epigenetic modifications in diabetic periodontitis
Objectives: Proinflammatory conditions as they occur in diabetic periodontitis diminish the ability of periodontal tissues to function physiologically, to heal, and to regenerate. Such conditions affect the gene promoters of periodontal connective tissue structural gene promoters through the inflammatory mediator NF-κB. Objective: To determine the effect of high glucose (HG) on gene expression and related histone methylation profiles in a diabetic periodontitis disease model.
Methods: Phenotype analysis, gene expression profiling and histone methylation mapping were performed using two diabetic animal models (db/db mice homozygous for the diabetes spontaneous mutation (Leprdb) and mice subjected to streptozotocin treatment) and a human periodontal ligament (hPDL) cell culture system.
Results: There was a significant loss of alveolar bone 5 days after initiation of streptozotocin treatment and a parallel increase in inflammatory gene expression levels, including IL-1β (4-fold), IL-6 (5.5-fold), DEFA4 (8-fold), and MMP9 (3.5-fold) versus a decrease in SUV39h (2-fold), ColIA1 (2-fold) and Col IIIA1 (1.5-fold). LPS inhibited hPDL mineralized lineage differentiation in osteogenic medium as revealed by a 50% reduction in alkaline phosphatase and a 10% reduction in alizarin red. LPS and HG conditions increased gene expression of IL-6 (2 and 3.5-fold, respectively) and MMP2 (3.5 and 6-fold, respectively). Immunofluorescence demonstrated an 8-fold increase of nuclear P65 accumulation in hPDL cells following treatment with either LPS, HG or a combination of HG and LPS. Treatment with LPS and HG enhanced enrichment of P65 (5 and 8-fold) and H3K4me3 (1.5 and 2-fold) on the IL-6 promoter accompanied by a 3-fold increase in SetD1 expression.
Conclusions: Long term-exposure to diabetic conditions resulted in H3K4me3 enrichment on the IL-6 gene promoter in diabetic periodontitis. Our study indicates that high glucose environments alter the integrity of periodontal connective tissues through changes in the chromatin state of proinflammatory gene promoters. Funding by NIDCR grant 1 F30 DE024352-01 is acknowledged.
Methods: Phenotype analysis, gene expression profiling and histone methylation mapping were performed using two diabetic animal models (db/db mice homozygous for the diabetes spontaneous mutation (Leprdb) and mice subjected to streptozotocin treatment) and a human periodontal ligament (hPDL) cell culture system.
Results: There was a significant loss of alveolar bone 5 days after initiation of streptozotocin treatment and a parallel increase in inflammatory gene expression levels, including IL-1β (4-fold), IL-6 (5.5-fold), DEFA4 (8-fold), and MMP9 (3.5-fold) versus a decrease in SUV39h (2-fold), ColIA1 (2-fold) and Col IIIA1 (1.5-fold). LPS inhibited hPDL mineralized lineage differentiation in osteogenic medium as revealed by a 50% reduction in alkaline phosphatase and a 10% reduction in alizarin red. LPS and HG conditions increased gene expression of IL-6 (2 and 3.5-fold, respectively) and MMP2 (3.5 and 6-fold, respectively). Immunofluorescence demonstrated an 8-fold increase of nuclear P65 accumulation in hPDL cells following treatment with either LPS, HG or a combination of HG and LPS. Treatment with LPS and HG enhanced enrichment of P65 (5 and 8-fold) and H3K4me3 (1.5 and 2-fold) on the IL-6 promoter accompanied by a 3-fold increase in SetD1 expression.
Conclusions: Long term-exposure to diabetic conditions resulted in H3K4me3 enrichment on the IL-6 gene promoter in diabetic periodontitis. Our study indicates that high glucose environments alter the integrity of periodontal connective tissues through changes in the chromatin state of proinflammatory gene promoters. Funding by NIDCR grant 1 F30 DE024352-01 is acknowledged.
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